In a wireless communication system, a terminal may register a specific Mobile Management Entity (MME) through an access process, and the terminal may receive a service via a corresponding MME in an MME pool area of the specific MME. Herein, an MME pool implies a group of unique MMEs in a Public Land Mobile Network (PLMN), and the MME pool area is an area managed by the MME pool. That is, when located inside the MME pool area, the terminal may receive a service without having to change a serving MME, and when located outside the MME pool area, the terminal must change the serving MME. For example, in a state where the terminal receives a service from a first eNodeB (eNB) and if a channel state between the terminal and the first eNB deteriorates or a movement of the terminal is detected, then the terminal may perform an X2 handover and/or an S1 handover so that the service can be provided from a neighboring second eNB.
The X2 handover implies a handover performed based on an X2 link between one eNB and another eNB in a state where the serving MME of the terminal is maintained. The S1 handover is a handover performed based on an S1 link between the eNB and the MME. When the terminal is not located outside the MME pool area, the serving MME may not be changed, and when the terminal is located outside the MME pool area, the serving MME may be changed.
As described above, the handover for supporting the service of the terminal may be performed based on the S1 link according to a situation. Therefore, upon a failure of an S1 link connection, there is a need to propose a detailed method for handling a handover using a corresponding S1 link.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.